Contact mounting



April 29, 1952 A. P. CHARBONNEAU EIAL 2,594,396

CONTACT uoummc Original Filed Dec. 15, 1944 Patented Apr. 29, 1952 CONTACT MOUNTING Allan P. Charbonneau and Frank J. Russell, Wauwatosa,

Wis., assignors to Cutler-Hammer, Inc.,

Milwaukee, Wis., a corporation of Delaware Original application December 15, 1944, Serial N 0. 568,316. Divided and this application March 9, 1951, Serial N0. 214,772

7 Claims.

This invention relates to improvements in elec- Another object of the invention is to facilitate manufacture of such contactors by simplifying the form and manner of assembling and/or adiusting the various parts thereof.

Another object is to provide an improved placement of the biasing springs associated with the plunger and the contactor, whereby a maximum portion of the plunger may consist of iron.

Another object is to provide for use of a plunger having an integral flange whereby leakage flux is substantially reduced and the pull in the sealed position is increased.

Another object is to so construct and assemble the parts as to provide for sealing of both the flange and the plunger face, whereby a sealed pull of relatively high value is obtainable.

Another and more specific object is to provide a method of assembling the parts wherein a cup member is engaged by the plunger flange and pressed by the latter to the desired position within the coil shell as an incident to initial engagement of the plunger face with the stationary core member.

Another object is to provide for utilization of said flange and said cup member to efiect determination of the length of the stroke of the magnet without requiring any further adjustment of said parts.

Another object is to provide a novel form of mounting bracket, a portion of which overlies and is attached to the core at the center of the coil; thus providing an increased thickness of magnetic material where the flux concentration is high.

Another object is to provide a novel sub-assembly of parts including a metal pin, a contactor carried thereby, and a bushing having threaded engagement with said pin whereby the pressure of said contactor against the stationary contacts may be preselected and thereafter maintained substantially constant.

Another object is to provide novel means affording self-alinement of the contactor with respect to the stationary contacts during normal use of the device.

Another object is to provide novel means enabling removal and/or replacement of the contactor and stationary contacts without in anywise affecting the initial adjustment of the switch parts.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of the invention which will now be described; it being understood that the embodiment illustrated is susceptible of modification in respect of certain structural details thereof and/or in respect of the manner of assemblingcertain of the parts.

In the drawings,

Figure 1 is an enlarged central sectional view of a contactor constructed in accordance with our invention.

Fig. 2 is an actual size plan view of the device, viewed from the left-hand side of Fig. 1.

Fig. 3 is a view, partly in elevation and partly in section, of a sub-assembly of certain parts illustrated in Fig. 1, and

Fig. 4 is a transverse section on the line 44 of Fig. 3, showing the means affording a drive fit of the bushing with respect to the flanged plunger of Fig. 1.

In the drawings the numeral l0 designates a base molded from any suitable insulating material. We prefer to employ either the molding material sold under the trade-name of Melmac or the molding material sold under the tradename of Bakelite. When base 10 is composed of Bakelite we prefer to mold or embed in one face thereof a pair of like sheet steel pole pieces H, l l which define the major portion of the length of the bottom wall of a transverse groove; the plane of which bottom wall is indicated by numeral 12. The adjacent ends of pole pieces H are spaced from each other a distance only slightly greater than the diameter of a circular opening l3 formed in base it), and the outer ends of said pole pieces are spaced only slightly from the opposite ends I 2 and I 5 of said base. Said pole pieces H are preferably provided at opposite sides thereof with upstanding flange portions (not shown) which extend. a distance approximately equal to the diameter of the contact tips and along the sides thereof. The outer edges of said flange portions are preferably coplanar with the out-er surface of said base. Said pole pieces therefore act in a known manner to assist in extinguishing any arcs which may be formed.

Each of the two stationary contacts comprises a flat and relatively thick punched plate It of metal of good electrical conductivity (preferably copper) having rounded ends l1 and I8, respectively. Each plate i6 is provided, in a concentric relationship to the rounded end 11 thereof, with a relatively large tapped opening I9 which is adapted to threadedly receive the shank 20 of a terminal bolt, the polygonal head of which is designated by numeral 2|. After complete threading of each shank 20 into an opening [9 the material of plate I6 is ring-staked around said opening I9, as indicated at 22, to lock said parts against relative movement, and to provide low resistance electrical contact.

Pole pieces II are provided respectively with openings 23 and base 10 is provided with openings 24 respectively alined therewith to provide for slid-able insertion of shanks 20 therethrough. A screw has its threaded shank 25 freely penetrating alined openings in base It and in the respective pole piece I l and taking into a tapped opening 25 in each plate 15 to rigidly secure the latter and its associated terminal bolt to said base. The head 21 of each screw is preferably accommodated within a countersink or recess in base I0, and a lockwasher 28 of suitable form is also preferably positioned between the screwhead and the bottom wall of the recess. If desired the remainder of each recess may be filled with a suitable wax or cement (not shown) to additionally restrain the screws and insulate the heads 2'! thereof.

Prior to assembly of each plate V5 with respect to base l as aforedescribed said plates have attached thereto in any suitable manner the silver base contact tips designated by numeral 29. In practice it is preferred that plates l6 be prepared in the manner disclosed in Patent No. 2,361,089, granted October 24, 1944, to I. W. Cox, and that a suitable metalliccomposition in powder form be united therewith by molding in the manner disclosed in said patent.

The shank 20 of each terminal bolt ha threaded thereonto a nut 30 which assists in rigidly attaching the same and its associated plate [6 to base I0; a lockwasher 3| of well known form preferably being interposed between said nut 30 and base II). also thereafter threaded onto each shank 20 to act as a clamp or binding element for the bared end of a circuit wire (not shown) which is preferably located between a metal washer 32 and.

the inner nut 30. A split lockwasher 33 is preferably interposed between washer 32 and the outer nut 30 to prevent accidental loosening of the latter.

The operating coil of the contactor is designated by numeral 34, said coil being wound in a known manner and impregnated with a suitable material to insure against failure thereof when in use. All surfaces of coil 34 are provided with a suitable insulating covering, as indicated by numerals 35, 35, 31 and 38. Said coil as thus covered is positioned within a seamless cup-shaped shell 39, preferably formed of steel; said shell having at its open end an outwardly offset or slightly enlarged portion 40, whereby a shoulder 4] is provided.

A relatively thin tube 42 of non-magnetic material such as brass is adapted to fit snugly within the central passage or opening in coil 34; said tube having positioned at one end thereof, and

rigidly and permanently attached thereto in any suitable manner, a core member 43 formed of magnetic material such as steel. Member E is provided at one end with a concentric countersink 44 and tapped recess 45; tne former being adapted to freely slide over the cylindrical enlarged portion 45 of a specially formed attaching A second nut 30 is bolt, whose threaded shank 41 takes into recess 45. Portion of said bolt is accommodated within alined openings 48 and 43 respectively formed in the end wall of shell Hand in the arm 50 of a supporting bracket. Another and substantially parallel arm 5! or" said bracket has an annular flange portion 52 formed thereon to accommodate that end portion of shell 33 which is of smaller diameter, and to snugly fit against the enlarged portion 45 and shoulder 4i aforementioned. Said special bolt is provided with a head 53 of hexagonal or other polygonal form; a lockwasher 54 being interposed between the same and bracket arm 53. Thus upon tightening of said bolt the shank 4'! draws core member 43 into direct engagement with the inner surface of the end wall 55 of the shell; the metal tube 42 being simultaneously moved therewith to the assembled position thereof illustrated.

Thereafter an annular punched plate 56 of insulating material, such as Bakelite is inserted within the enlarged portion 33 of the shell in a relation to closely surround and assist in positioning the projecting end of tube 42. A steel cup washer 51 is then inserted into said enlarged portion 40 of the shell; said cup washer having an outer annular flange 58 adapted to slidably fit within said enlarged portion, and an inner, relatively shorter, annular flange 59 adapted to surround at least a portion of the projecting end of tube 42.

The plunger of the contactor is composed of magnetic material, the same having a substantially cylindrical main portion 60 and an integral annular flange 6| at the outer end thereof. As shown the end 62 of the aforementioned core 43 is preferably of substantially cone-shape, and the adjacent end of plunger 60 is correspondingly of hollow cone-shape, as shown at 63 to fit snugly thereagainst. The arrangement is such that flange 6| overlies the upper edge of the inner flange 59 on the cup washer, so that when plunger 50 is pressed inwardly until the surface 63 seats firmly against the cone-shaped surface 52, the flange 5| will have simultaneously engaged flange 59 to force the cup washer 51 the desired distance into the metal shell. In this manner simultaneous sealing of surface 53 with surface 62 and of flange 6| against flange 59 may be insured. After cup washer 5! is thus properly positioned, such positioning may be made rigid and permanent in any suitable manner, such as by welding or soldering said cup washer and shell to each other.

The bridging contactor comprises a fiat punched plate 66, preferably of copper; said plate having circular tips 29, 29, like those aforedescribed, rigidly attached to opposite ends thereof. Said contactor tips 29 are properly spaced (see Fig. 1) for alinement thereof with tips 29 of the stationary contacts. Plate 65 preferably has its ends 67 and 68 rounded to conform substantially with the contours of the tips 29 mounted thereon. Said plate 56 is also provided with a central circular opening 69, within which an insulatin bushing H1 is positioned; said bushing ill being preferably molded in situ, Bushing 16 is preferably composed of Melmac, which is characterized by its effective resistance to damage by heating or arcing. Bushing 18 has formed integrally therewith the annular flanges H and I2, which overlie the respective opposite faces of plate 65 around said opening 69. A recess 13 is formed in bushing 18 to accommodate the substantially correspondingly shaped cup washer 14, which is preferably formed of brass.

A coiled compression spring 15 has one end seated within cup washer 14; a metal pin 16, preferably of steel, penetrating aligned central Openings in bushing I8 and cup washer 14, and having an annular groove I1 formed therein adjacent one end thereof. A horseshoe-shaped washer I8 is pressed into groove I1, and a metal cup Washer 19 is positioned upon pin 15 to surround washer I8 and prevent accidental lateral displacement thereof; the other end of spring I5 abutting against the exterior surface of cup washer 19.

The outer surface 88 of bushing I8 is preferably in the form of a segment of a sphere, for cooperation with the correspondingly shaped concave bearing surface BI upon a molded hollow insulating member 82, also preferably composed of Melmac. Member 82 has a relatively short inner flange 83 and a relatively longer outer flange 84, between which one end of a coiled compression spring 85 (Fig. 1) is adapted to seat. Prior to assembly of spring 85, however, the threaded end portion 86 of pin I6 is screwed into the internally threaded portion 81 of a bushing 88, preferably machined from a steel rod. The edge of the aforementioned flange 83 is adapted to abut against the adjacent end of bushing 88, whereby upon a predetermined degree of turning of pin 18 relatively to bushing 88, spring 15 will be compressed to a degree to insure the desired pressure of the bridging contactor against the stationary contacts when all of the parts are finally assembled. In other words, the adjustment of pin 16 with respect to bushing 88 is merely such as to provide the desired degree of compression of spring 15, as measured in pounds. When the desired adjustment has been effected, a quantity of molten solder 89 or the like is dropped into the end of bushing 88 to overlie and surround the reduced end portion 98 of pin 18 to restrain said parts against further movement relatively to each other. Bushing 88 is provided with an end portion 9I of reduced external diameter, toward which the intermediate portion 92 is tapered as shown. The main body portion of bushing 88 has four equally spaced longitudinal grooves formed therein by rolling or otherwise in such manner that four pairs of longitudinal fins or projections 93 are provided (Figs. 3 and 4) Fins 93 are of such lateral dimensions as to provide for a force fit of bushing 88 into a recess 94 in the outer end of plunger 88; bushing 88 being pressed inwardly to a degree to afford the proper wear allowance of bridging contactor 88.

A relatively thin walled molded insulating cover member 95 is provided to house or enclose contactor 66; said member 95 having a pair of openings formed therein (one on each side of the hollow dome or extension 96, (Fig. 1). Base I8 has a pair of upstanding lugs formed integrally therewith on opposite sides of the groove I2; one of said lugs being shown at 9'! in Fig. 1. Said lugs serve to guide the reciprocating movements of contactor 68, and each of said lugs has molded therein and projecting outwardly therefrom a threaded stud (not shown) respectively penetratand 56 (Fig. 1), such extension of plate 37 being "contactor support comprising a metal pin, said pin having an annular groove adjacent one end thereof, a horeshoe-shaped washer insertable 8 ing said openings in cover 95; a pair of nuts (not shown) being threaded onto said studs to clamp cover 95 in proper position upon base I8.

The aforementioned bracket arm 5I is provided with perforations (Fig. 1) to be alined with the tapped recesses in metal inserts 98, 98 in base I8; suitable screws 99 and lock-washers I88 being provided for clamping said bracket arm and its associated parts to base I8.

The connecting portion I8=I of the bracket is provided with openings I82 and I83 to accommodate the shanks of suitable mounting bolts or screws (not shown) for attachment of the complete device to a panel or other suitable support.

The aforementioned arm 58 of the supporting bracket is provided with a relatively small opening I84 which is adapted to accommodate a raised portion or boss I85 formed upon the end wall 55 of shell 39, whereby relative rotation of }the shell and bracket is prevented. Although said bracket is formed of relatively thin sheet metal, the same is provided with suitable embossed ribs and fillets, as shown, to strengthen the same and resist distortion thereof when in use.

- As shown in Fig. 2, base I8 is provided with an integral extension I86 having a downwardly off set ledge I81, which is adapted to accommodate, in a substantially flush relationship, the lateral extensions of the insulating members or plates 31 designated by numeral I88 in Fig. 2. Interposed between said extensions are a pair of relatively thin copper ribbons, shown in dotted lines at I89 and H8; said ribbons being attached to opposite ends of the wire of coil 34 and having enlarged sends in the form of eyelets which are upset over the outer surface of plate 31, as indicated at III and H2 in Fig. 2. Screws I I3 and I I4 have their shanks extending upwardly through alined openngs in base extension I86, plates 56 and 37 (and eyelets III, H2), and one or more nuts H5, H6 are associated with said screws to clamp the parts in position and to provide for attachment of suit- If desired a bus member I I! We claim: 1. In an electromagnetic contactor, a bridging into said groove, a cup washer positioned upon said pin and having its flange overlapping the fedge of said first mentioned washer to normally prevent displacement of the latter from said groove, a bridging contactor also positioned upon said pin, said bridging contactor having a perforated insulating member molded in situ there- ;on and surrounding said pin, a coiled compression spring interposed between said cup washer and one surface of said insulating member, a

-.-second perforated insulating member positioned upon and surrounding said pin and against which the other surface of said first mentioned insulating member is adapted to bear, the engagwing surfaces of said insulating members being respectively of convex and concave form to provtively to said pin and with respect to associated vide for self-alinement of said contactor relastationary contacts when in use, said pin having a thread formed upon the other end thereof, and an internally threaded metal bushing adjustable upon the last mentioned end of said pin to pro- 7 vide a predetermined degreeof compression of said spring, whereby the pressure of said contactor when in bridging relationship tothe stationary contacts may be preselected. r

2. In an electromagnetic contactor, a bridging contactor. support comprising'a metal pin, said pin having an annular groove adjacent 'o'neend thereof, a horseshoe-shaped washer insertable into said groove, a cup washer positioned upon said pin and having its flange overlapping the edge of said first mentioned washer to normally prevent displacement of the latter from said groove, a bridging'contactcr also positioned upon said pin, said bridging contactor having a perforated insulating member molded in situ thereon andsurrounding said pin, a coiled compression spring interposed between said cup washer and one surface of said insulating member, a second perforated insulating member positioned upon and surrounding said pin and against which the other surface of said first mentioned insulating member is adapted to bear, the engaging surfaces of said insulating members be ing respectively of convex and concave form to provide for self-alinement of said contactor relatively to said pin and with respect to associated stationary contacts when in use, said pin having a thread formed upon the other end thereof, an internally threaded metal bushing adjustable upon the last mentioned end of said pin to provide a predetermined degree of compression of said spring, whereby the pressure of said contactor when in bridging relationship to the stationary contacts may be preselected, and means associated with said pin and said bushing to secure the same against further movement relatively to each other after the desired adjustment thereof has been eifected.

' 3. In an electromagnetic contactor, a bridging contactor support comprising a metal pin, said pin having an annular groove adjacent one end thereof, a horseshoe-shaped washer insertable 'into said groove, a cup washer positioned upon said pin and having its flange overlapping the edge of said first mentioned washer to normally prevent displacement of the latter from said groove, a bridging contactor also positioned upon said pin, said bridging contactor having a perforated insulating member molded in situ thereon and surrounding said pin, a coiled compression spring interposed between said cup washer and one surface of said insulating member, a second 7 perforated insulating member positioned upon and surrounding said pin and against which the other surface of said first mentioned insulating member isadapted to bear, the engaging surfaces of said insulating members being respectively of convex 'and concave form-to provide for-self-alinement of said contactor relatively to said pin'and with respect to associated stationary contacts when in use, said pin having a thread formed upon-the other end thereof, an internally threaded inet'al bushing adjustable upon the last mentioned end-of said pin to provide a predetermined degree of compression of said spring, whereby the pressure of said contactor when in bridging relationship to the stationary contacts may be preselected, means associated with said pin and said bushing to secure the same against further movement relatively to each other afterthe desired adjustment thereof has been eilected, said last mentioned means comprising a quantity of molten solder or the like interposed'between the threaded end of said pin and'said bushing; and

said pin end having a portion of reduced diameter to accommodate a portion of said solder.

4. In an electromagnetic contactor, a bridging contactor support comprising a metal pin, said pin having an annular groove adjacentone end thereof, a horseshoe-shaped washer insertable into said groove, a cup washer positioned upon said pin and having its flange overlapping the edge of said first mentioned washer to normally prevent displacement of the latter from said groove, a bridging contactor also positioned on said pin, said bridging contactor having a perforated insulating member molded in situ thereon and surrounding said pin, a coiled compression spring interposed between said cup washer and one surface of said insulating member, a second perforated insulating member positioned upon and surrounding said pin and against which the other surface of said first mentioned insulating member is adapted to bear, the engaging surfaces of said insulating members being respectively of convex and concave form to provide for self-adjustment of said bridging contactor relatively to said pin and with respect to associated stationary contacts when in use, and a second coiled compression spring associated with said second insulating member to insure at least a predetermined degree of frictional engagement between said convex and concave surfaces. e

5. In an electromagnetic contactor, a bridging contactor support comprising a metal pin, a spring abutment member removably attached to said pin adjacent one end thereof, a bridging contactor carried by said pin, associated means for insulating said contactor from said pin, a coiled compression spring interposed between said abutment and said insulating means, other insulating means positioned upon and surrounding said pin and against which said first mentioned insulating means is adapted to bear, the engaging surfaces of said insulating means being respectively of convex and concave form to provide for self-adjustment of said contactor relatively to said pin and with respect to associated stationary contacts when in use, said pin having a thread formed upon the other end thereof, and an internally threaded metal bushing adjustable upon the last mentioned end of said pin to provide a predetermined degree of compression of said spring, whereby the pressure of said contactor when in bridging relationship to the stationary contacts may be predetermined.

6. In an electromagnetic contactor, a bridging contactor support comprising a metal pin, a spring abutment member removably attached to said pin adjacent one end thereof, a bridging contactor carried by said pin, associated means for insulating said contactor from said pin, a coiled compression spring interposed between said abutment and said insulating means, other insulating means positioned upon and surrounding said pin and against which said first mentioned insulating means is adapted to bear, the engaging surfaces of said insulating means being respectively of convex and concave form to provide for self-adjustment of said contactor relatively to said pin and with respect to associated stationary contacts when in use, said pin having a thread formed upon the other end thereof, an internally threaded metal bushing adjustable upon the last mentioned end of said pin toprovide a predetermined degree of compression of said springiwhereby the pressureof said contactor when in bridging relationship to the stationary contacts may be predetermined, a stationary insulating member relatively to which said pin and bushing are adapted to move, and a coiled compression spring interposed between said last mentioned insulating member and said second mentioned insulating means to bias said pin and bushing for movement thereof in one direction.

7. In an electromagnetic contactor, a bridging contactor support comprising a, metal pin, a spring abutment member removably attached to said pin adjacent one end thereof, a bridging contactor carried by said pin, associated means for insulating said contactor from said pin, a coiled compression spring interposed between said abutment and said insulating means, other insulating means positioned upon and surround ing said pin and against which said first mentioned insulating means is adapted to bear, the

engaging surfaces of said insulating means being respectively of convex and concave form to provide for self-adjustment of said contactor relatively to said pin and with respect to associated stationary contacts when in use, said pin having a thread formed upon the other end thereof, an internally threaded metal bushing adjustable upon the last mentioned end of said pin to provide a predetermined degree of compression of said spring, whereby the pressure of said contactor when in bridging relationship to the stationary contacts may be predetermined, a stationary insulating member relatively to which said pin and bushing are adapted to move, a coiled compression spring interposed between said last mentioned insulating member and said second mentioned insulating means to bias said pin and bushing for movement thereof in one direction, and means including a plunger having a recess to forcibly accommodate said bushing whereby a predetermined degree of wear allowance of said contactor may be provided, said plunger having a flange engageable with said stationary insulating member to positively limit the degree of movement of said pin and bushing under the bias of said second spring.

ALLAN P. CHARBONNEAU. FRANK J. RUSSELL.

N 0 references cited. 

